Replacing the interior in your boler
is a big task. It also seems to be a controversial one on here. There will be an overwhelming number of posts telling you not to do it.
I replaced the carpet on the walls of my Boler, best thing I did. BUT it was not the easiest thing I did either. Especially the ceiling, it took me more than one attempt to get the ceiling to work the way I wanted. In all honesty replacing the carpet on the walls was no harder than hanging wall paper. And here is another but, I had all of the windows
out, the kitchen was removed as were the dinette seats and the upper cabinets were loose.
As for removing the glue from a previous reno. Good luck. I tried a variety of tools. Using a wire wheel just covered me in fiberglass and made the glue sticky and glob together. I found scraping the shell with a large sharp chisel worked best, but be careful the shell is thin.
I reapplied new carpet that I bought off of Paul Neumeister (well known in Ontario and the northern states) . It was actually the leftover from Paul's own Boler when he replaced his interior. I did not use contact cement however, it didn't work since it seeped through the carpet. I used exterior carpet glue, it was great.
Either way remember it's your Boler and only you know how much of a task is too big for you.